Teachers in traditional public schools have far worse rates of chronic absenteeism than those who teach in charter schools, according to a report out today. But a union official in Michigan questioned the findings.

That report was released by the Thomas B. Fordham Institute, an education reform advocacy organization based in Washington, D.C., and Ohio.

The findings: Nationwide, 28.3% of teachers in traditional public schools are chronically absent, compared to 10.3% in charters.

A teacher is chronically absent after missing more than 10 days of school for sick or personal leave.

In Michigan, the rate for teachers in traditional public schools was 24.7%, while the rate was 12.4% for charter teachers.

Teachers in charter schools that are unionized also tended to have higher chronic absenteeism than charters that aren't unionized, the report said.

David Griffith, senior research and policy associate at the institute, said a clear recommendation from the findings is this: "That we should reduce the number of paid sick days that teachers get per year."

Griffith said that nationwide, teachers in traditional public schools receive an average of 12 paid sick or personal days.

But Doug Pratt, spokesman for the Michigan Education Association, the state's largest teacher's union, questioned the findings, saying, "Consider the source," and noting Fordham's support of school choice and charter schools.

Pratt also said teachers often end up taking days off because of extended illnesses or because they're caring for a sick relative.

He said that considering the equivalent of two weeks missed as chronic absenteeism is misleading for a profession "whose job it is to spend time with 30 kids every day.

"When you walk into a building in the middle of winter, the flu bug that's going around and sidelining students and staff can spread like wildfire," Pratt said.

He said that in charters, "very few have organized themselves to bargain those days off," and have to show up for work sick to keep their jobs.

"It comes down to a question of do you want sick teachers in front of kids. Do you want a teacher whose parent or partner is undergoing chemotherapy that morning — and because of the reasonable amount of time they've bargained — gets to be with their family member and take care of what they need to? Or should they be in front of students distracted?"

Dan Quisenberry, president of the Michigan Association of Public School Academies, a charter school advocacy group, had an angry response to Pratt's comment that charter teachers have to show up for work sick, saying Pratt and the MEA should be "ashamed of themselves for that unfounded, irresponsible allegation."

Quisenberry said charter teachers "don't need to be told when to show up to work and when to stay home. They're professionals, and they're going to do what's right for themselves and for their students."

Griffith said many states are planning to use chronic student absenteeism as one way to evaluate schools. Fordham believes they should also look at teacher chronic absenteeism. None, including Michigan, have done so, he said.

"Why are we holding students accountable for their attendance," and not teachers? Griffith asked.

"We're not saying that teachers should never miss a day of school," Griffith said. "We're just saying that it certainly looks to us that there's room for improvement in certain places, in certain states."

Pratt took issue with the idea that not having chronic teacher absenteeism in the state's improvement plan means teachers aren't being held accountable.

"Michigan is holding teachers accountable for absences as part of their evaluations," Pratt said. "It’s a part of evaluation models school districts are using all over the state."

The state with the worst rate: Hawaii, where the data show 79% of traditional public school teachers are chronically absent. For charters, it was 23%.

Alaska was the only state where charter teachers were more likely to be chronically absent.

Data used in the research came largely from the U.S. Department of Education and are for the 2013-14 school year. The researchers also used data from the National Council on Teacher Quality and the National Alliance for Public Charter Schools.

Randi Weingarten, the president of the American Federation of Teachers, said in a statement this morning that Fordham should be asking "how we recruit, retain and support teachers for America's schools." She pointed to research from the Organisation for Economic Co-operation and Development that found U.S. teachers "are paid much less than their similarly educated peers, teach longer hours, and have less time to prepare their lessons than their international counterparts."

She also questioned the data, which is submitted to the federal education department's Office of Civil Rights.

"The Fordham Institute's comparison with charter schools is a snapshot that doesn't support an apples-to-apples comparison, because definitions, data collection and responses vary widely between and within districts and schools," Weingarten said. "You can't even compare one school district with another, let alone charter schools with other charters or charters with school districts."